7-4. Air conditioner operates, but abnormalities are observed.
7-4-1. Operation does not switch from HEAT to COOL (or COOL to HEAT)
7-4-2. Poor cooling or heating
7-4-3. Excessive cooling or heating
NO
• Set temperature is suitable.
Set temperature to higher or
lower value using thermostat
on the control panel.
Air filter is clogged.
Temperature
difference
is small.
YES
Temperature difference between
suction and discharge air is
large enough (approx. 10 deg. or more).
Possibility of
gas shortage.
• Measure temperature of suction and
discharge air of air conditioner.
Charge refrigerant
gas (R22).
Check for clogging of air filter.
• Fan speed is set to LOW.
Clean filter.
Set fan speed to
HIGH.
• Review cooling load estimate,
if performance of air conditioner is
normal.
Reduce cooling or heating
load or replace the air
conditioner with larger
capacity.
• Measure resistance of 4–way valve's
winding.
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